Prenatal alcohol exposure can have a variety of behavioral and physical consequences for the developing offspring. While the incidence of alcohol consumption during pregnancy may be decreasing, many clinical studies suggest that women that continue to consume alcohol during pregnancy are also more likely to consume other drugs as well. One of the more frequent drug combinations consumed is alcohol and cocaine. The purpose of this application is to use a rodent model to assess the effects of "third trimester" exposure to this drug combination. The third trimester is a period of rapid CNS growth and proliferation commonly known as the "brain growth spurt" and evidence suggests that the CNS is vulnerable to injury during this period. In rats, the analogous period of development actually occurs during the first two weeks after birth. Therefore, in order to study"third trimester" effects, the drugs must be given to the neonatal rat. An artificial-rearing procedure will be employed in which pups are implanted with an intragastric cannula an fed a milk formula with the drug added to the milk. A major advantage of this artificial rearing procedure is that it allows the amount of food consumed (and drug consumed) to be controlled by the experimenter. This allows complete control over drug exposure without any concomitant undernutrition or change in maternal behavior. Alcohol and cocaine will be administered both separately and in various combinations to allow us to study the interactive effects of these drugs on development. Many of the studies will focus on clinically- relevant behaviors that are believed to be sensitive to prenatal/neonatal exposure to one of these drugs. This strategy will allow us to focus on the possible interactions when exposure occurs to known quantities of both of these drugs. In addition, tasks that have not yet been examined following neonatal ethanol or cocaine exposure have been proposed. The results from these studies should provide important information regarding the interactive effects of neonatal exposure to ethanol and cocaine as well as providing new information regarding the effects of neonatal exposure to each of these drugs independently. These findings should also provide a basis for further direction regarding the mechanisms for these drugs effects during early development.